Rework TPM measurements

Rework TPM measurements to use fewer PCRs. After discussion with upstream,
it's preferable to avoid using so many PCRs. Instead, measure into PCRs 8
and 9 but use a prefix in the event log to indicate which subsystem carried
out the measurements.

grub-core/lib/cmdline.c

@@ -105,8 +105,8 @@ int grub_create_loader_cmdline (int argc, char *argv[], char *buf,
 
   *buf = 0;
 
-  grub_tpm_measure ((void *)orig, grub_strlen (orig), GRUB_CMDLINE_PCR,
-		    "Kernel Commandline");
+  grub_tpm_measure ((void *)orig, grub_strlen (orig), GRUB_ASCII_PCR,
+		    "grub_kernel_cmdline", orig);
 
   return i;
 }